Long-term monitoring of tropical bats for anthropogenic impact assessment: Gauging the statistical power to detect population change

Bats are ecologically important mammals in tropical ecosystems; however, their populations face numerous environmental threats related to climate change, habitat loss, fragmentation, hunting, and emerging diseases. Thus, there is a pressing need to develop and implement large-scale networks to monitor trends in bat populations over extended time periods. Using data from a range of Neotropical and Paleotropical bat assemblages, we assessed the ability for long-term monitoring programs to reliably detect temporal trends in species abundance. We explored the magnitude of within-site temporal variation in abundance and evaluated the statistical power of a suite of different sampling designs for several different bat species and ensembles. Despite pronounced temporal variation in abundance of most tropical bat species, power simulations suggest that long-term monitoring programs (?20 years) can detect population trends of 5% per year or more with adequate statistical power (?0.9). However, shorter monitoring programs (?10 years) have insufficient power for trend detection. Overall, our analyses demonstrate that a monitoring program extending over 20 years with four surveys conducted biennially on five plots per monitoring site would have the potential for detecting a 5% annual change in abundance for a suite of bat species from different ensembles. The likelihood of reaching adequate statistical power was sensitive to initial species abundance and the magnitude of count variation, stressing that only the most abundant species in an assemblage and those with generally low variation in abundance should be considered for detailed population monitoring.     

Study of the interaction of pancreatic lipase with procyanidins by optical and enzymatic methods

The interactions between porcine pancreatic lipase (PL) and grape seed procyanidins were studied by an enzymatic assay, fluorescence quenching, nephelometry, and dynamic light scattering (DLS). An inhibitory effect of grape seed procyanidins on lipase hydrolytic activity was found. Both the inhibition of lipase activity by procyanidins and the respective quenching of intrinsic protein fluorescence increased with the average degree of polymerization of the tested procyanidins. The association between procyanidins and enzyme involves a specific interaction as inferred from the fluorescence assays despite not changing significantly the tertiary structure of the protein. For all tested procyanidins it was shown, both by DLS and by nephelometry, that an increase in aggregation occurs up to a stoichiometric maximum after which further procyanidin addition causes a decrease in aggregation of aggregates. The maximum size of aggregates was shown to be closely related to the maximum overall aggregation. It was also shown that the inhibition of enzyme activity is to a large extent independent of the formation of aggregates.     

Responses to heat stress in commercial and local broiler stocks. 2. Developmental stability of bilateral traits.

1. Developmental stability of bilaterally symmetrical traits was measured in two fast (G1 and G2) and one slower growing (G3) broiler stocks when conditioned (chicks exposed to 36 degrees C for 24 h at 5 d of age) or food restricted (food withdrawn 2 h before the hot period and chicks fed between 17.00 and 08.00 h) during heat stress administered daily from 28 to 49 d of age. 2. Length of face, length, width and weight of shanks, weights of P. major and P. minor muscles, and weights of lung and caeca were chosen as bilateral traits representative of skeletal, muscle, respiratory and digestive systems. 3. Development of skeletal bilateral traits was affected primarily by genotype and sex. The heart:lung ratio decreased with conditioning in stocks G1 and G2 at 21 d. Face length, shank length and shank weight exhibited antisymmetry, whereas shank width and weights of P. minor, lung and caeca exhibited fluctuating asymmetry and antisymmetry. For P. major weight, there was directional asymmetry. 4. In general, relative asymmetry of skeletal traits was lower than for traits associated with muscle and with respiratory and digestive systems. Relative asymmetry of P. major weight was lower in conditioned and G3 broilers than in their respective counterparts. 5. If relative asymmetry is a valid indicator, item heat stress may be less in slower growing and conditioned broilers.     

Consequences of less intensive farming on the landscape: an example of vegetation dominance by Chaerophyllum aureum in the meadows of a Pyrenean valley in France

The impact of agricultural practices on the dynamics of weed invasion in a rural landscape was studied by describing the spatial distribution of Chaerophyllum aureum populations colonising less intensive managed hay meadows. Polyphenol compounds were used as individual markers to identify the structure of C. aureum diversity, in terms of its scale and patterns, within and between fields along the bottom of a Pyrenean valley. The results revealed, firstly, the existence of a dominant `genotype' successfully colonising the entire area, and secondly, the maintenance of high levels of polyphenol diversity within five different populations. This spatial arrangement of `genetic' population diversity was obviously not related to the natural reproduction and dispersal patterns of this species, but to human practices of hay production, the principal effect of which is to mix seeds of different genetic origin and thus accelerate and amplify the colonisation process of adapted `genotypes'.     

Effects of strain, maternal age and sex on morphological characteristics and composition of tibial bone in broilers.

1. This study was to determine the effects of strain, age of the maternal flock and sex on morphological characteristics and composition of tibial bone of broilers from hatch to 48 d of age. 2. A total of 600 chicks was obtained from 2 strains of broiler breeder flocks (150/chicks/strain/maternal age). Maternal flock age was classified as young (32 to 35 weeks of age) or old (56 to 58 weeks of age). Birds were reared under standard feeding and lighting regimes. 3. On day 1, 16, 32 and 48, twelve birds were selected at random from each maternal group, strain and sex and killed. The wet bone weight and volume were measured. Morphological characteristics of tibia were determined using radiography. Bone breaking strength was tested. Tibia dry matter, ash content, mineral density and collagen level were determined. 4. A quadratic increase occurred with increase in age of broilers for all variables, except proximal width, medial cortex thickness and distal condyle width which increased in a linear manner. 5. Maternal age had a significant effect only on the variably measured at the time of hatch. On day of hatch bone weight, ash content and bone volume were affected by maternal age, but the extent of this also depended on the strain. 6. The differences observed between strains for bone anatomy and bone mineralisation during the rapid growth period of 16 d were not significant at later ages, with the exception of bone volume. Differences between sexes were evident from 16 to 49 d of age with females having lower values.     

Teratosphaeria gauchensis associated with trunk,stem and foliar lesions of Eucalyptus globulus in Portugal

Teratosphaeria gauchensis and T. zuluensis both cause a stem canker of eucalypts that leads to serious damage in various parts of the world. Until recently, this disease was unknown in Portugal. Nevertheless, severe damage to Eucalyptus globulus has been observed in Portugal since 2006 when symptoms appeared as necrotic spots on young green stems and leaves, twig lesions, and dark oval‐shaped lesions on stems and trunks. The isolates from affected E. globulus tree plantations were identified using sequence data of the ITS1‐5.8S‐ITS2 and EF‐1α clusters, together with morphological characteristics. Based on these results, the causal organism was identified as T. gauchensis, which represents the first report of this pathogen from Portugal.     

Impact of natural and human selection on the frequency of the F1 hybrid between cultivated and wild pearl millet (Pennisetum glaucum (L.) R. Br.)

In the Sahel, pearl millet yields are affected by the proportion of hybrid phenotype plants resulting from genetic mixing between domesticated and wild forms. Man counteracts this mixing by applying a production method, the efficiency of which is quantified in this study. Under experimental conditions, cultivated and wild pearl millet were hybridised in order to obtain cultivated pearl millet seeds including a known proportion of F1 hybrids tagged by two different allozymes. These seeds were sown in the field and the cultivation was conducted following practices common in the Sahel. The evolution of the survival rate of plants and the frequency of hybrids were followed over several stages during the season: sowing, germinating, emergence, thinning, flowering and maturing of the seeds. Owing to plant mortality in the experiment, the average tendency was a hybrid frequency that decreased steadily in the first part of the growing season from 42% during germination, to 37% at emergence. It then fell to 17% after the thinning of the plantlets by the farmer. At the end of the cycle, after thinning, only 11% of mature plants were hybrids. Thus, under the combined pressures of natural and human selection, the frequency of hybrids in the field declined drastically. In interaction with natural pressure, the farmer's practices of selection of seeds, sowing in pockets and thinning have the combined effect of heavily selecting the cultivated genotype and limiting without completely preventing the introgression of wild pearl millet genes into the cultivated genome. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mapping QTLs for Witches' Broom (Crinipellis Perniciosa) Resistance in Cacao (Theobroma Cacao L.)

Molecular markers (RAPD, AFLP and microsatellites) were used to generate a linkage map and to identify QTLs associated to witches' broom (Crinipellis perniciosa) resistance in cacao (Theobroma cacao), using 82 individuals of an F₂ population derived from the clones ICS-1 (susceptible) and Scavina-6 (resistant). Fifteen evaluations of the number of brooms have been carried out in six years (1997–2002). In order to increase the precision and accuracy in the measures of resistance, each F₂ plant was cloned in three replications in a randomized block design with single-tree plots and evaluated over 2 years. Three hundred and forty-two markers were obtained, being 33 microsatellites, 77 AFLPs and 232 RAPDs. The distribution of the number of brooms in the F₂ population was skewed to resistance, suggesting the involvement of major genes controlling resistance and the repeatability estimated for resistance was 44%. A strong putative QTL was detected as being related to witches' broom resistance. Associated to this QTL, the microsatellite mTcCIR35 explained 35.5% of the phenotypic variation in resistance. This marker is being used for marker-assisted selection in Scavina-6 progenies, including those selected in private plantations, as an auxiliary tool to the phenotypic selection.